Lymphatic System and Immunity Flashcards
Exam 2
What are the functions of the Lymphatic System?
- drain excessive ECF
- transport dietary fats
- defense
- return leaked plasma proteins to the blood
Resistance
the ability to ward off the pathogens that produce disease
What is lack of resistance called?
Susceptibility
What are the 2 areas of disease resistance?
Provide Definitions
- Nonspecific Resistance: includes defense mechanisms that provide general protection against invasion by a wide range of pathogens
- Immunity: involves activation of specific lymphocytes that combat a particular pathogen or other foreign substance
Extracellular Fluid
fluid surrounding the cell
How does swelling occur in the body?
excess ECF fluid not drained
Edema
- swelling that is cold to the touch
- cell retains normal size
Inflammation
- swelling that is warm to the touch
- cell are larger than normal
What 2 components make up the Extracellular Matrix?
- extracellular fluid
- fibers
Lacteal
special lymphatic vessel (capillary) where all dietary lipids are absorbed and delievrs chyle to the blood
Chyle
milky-white, fatty lymph
Why do lipids bypass the liver?
they are sticky
Lipoproteins
Definition and Name Them
lipid carriers in the blood
- Chylomicrons
- High Density Lipoprotein (HDL)
- Low Density Lipoprotein (LDL)
- Very Low Density Lipoprotein (VLDL)
Name the cells of the Lymphatic System
- Macrophages
- Lymphocytes (B & T)
Macrophages are basically…
fused monocytes
Where are Macrophages found?
in the ECM
Vasodilation
increase in the diameter of lumen of the blood vessel
What is lymph composed of?
- dead tissue cells
- dead leukocytes
- bacteria
- dietary fats
What color is lymph and why?
milky due to dietary fats
What are the Vessels of the Lymphatic System?
- Lymph Capillary
- Lymph Node
- Lymph Trunks
- Cisterna Chyli (AKA Confluence Capillary)
- Lymph Ducts (2)
The Path Lymph Flows
lypmh capillaries -> collecting lymphatic vessels -> lymphatic trunks -> lymphatic ducts
Lymph Capillary
- starting location for lymph transport
- weave between tissue cells and blood capillaries
- found throughout the body except in avascular tissue, the CNS, portions of the spleen, and red bone marrow
Lacteal
- a lymphatic capillary in the villus of the small intestine
- where all dietary lipids are absorbed
How do Lymph Capillaries differ from Blood Capillaries?
- have slightly larger diameter
- Can take up larger molecules (ex: proteins, cell debris, pathogens, cancer cells)
- collagen fibers anchored to matrix and one-way minivalves increase permeability
Collecting Lymphatic Vessels
- receive fluid from lymph capillaries
- consist of collecting vessels, trunks, and ducts
How to Collecting Lymphatic Vessels differ from Veins?
- thinner walls
- more internal valves
- anastomose more (joining together)
Lymphatic Trunks
- drain large areas of body
- formed by union of largest collecting vessels
List the principal lymphatic trunks
And how are they formed?
- paired lumbar trunks
- paired bronchomediastinal trunks
- paired subclavian trunks
- paired jugular trunks
- single intestinal trunk
Formed from the exiting vessels of lymph nodes
Lymphatic Ducts
- receive lymph from the lymphatic trunks
- empties lymph into venous circulation at respective junction of internal jugular and subclavian veins
Name the 2 Lymph Ducts
- Right Lymphatic Duct
-Thoracic Duct
Thoracic Duct
- main collecting duct of the lymphatic system
- begins as the cisterna chyli
What regions do the Thoracic Duct drain lymph from?
Where does is drian lymph into?
- left head region
- left neck region
- left thoracic region
- left arm region
- other areas below diaphragm
drains into venous blood via the left subclavian vein
What regions do the Lymphatic Duct drain lypmh from?
Where does is drian lymph into?
- right head region
- right neck region
- right thoracic region
- right arm region
drains into venous blood via the right subclavian vein
Lymphedema
severe localized edema caused by anything that prevents the normal return of lymph to the blood
ex: tumor blocking the lymphatics
ex: lymphatics removed during cancer surgery
Layers of the Lymphatic Vessel
only 1 layer - endothelium
attached to basement membrane
Name the Encapsulated Organs of the Lymphatic System
- spleen
- lymph node
- bone marrow
- MALT (Mucosa-Associated Lymphoid Tissue)
- Peyer Patches
- Thymus Gland
Name the Uncapsulated Organs of the Lymphatic System
- appendix
- tonsils (adenoid/pharingeal; palatine; linguinal)
Primary lymphatic organs
the red bone marrow and the thymus gland that produces and matures B and T cells
Secondary lymphatic organs
areas where mature lymphocytes first encounter their antigen and become activated
- lymph nodes
- spleen
- MALT (mucosa-associated lymphoid tissue) that form tonsils and diffuse lymphoid tissues
most immune responses are in secondary lymphatic organs
Lymphatic nodules
clusters of lymphocytes that stand guard in all mucous membranes
Where does interstitial fluid drain into?
lymph capillaries
List the passage of lymph
arteries -> blood capillaries (blood) -> interstitial spaces (fluid) -> lymph capillaries (lymph) -> lymphatic vessels -> lymph trunks -> thoracic OR right lymphatic duct -> subclavian veins (blood)
What does lymph flow as a result of?
- the milking action of skeletal muscle contractions and respiratory movements
- also aided by lymphatic vessel valves that prevent backflow of lymph
Thymus Gland
- lies between the sternum and the heart
- secrete Thymosin (endocrine)
- site of lymphocyte maturation, teaching them to become T-cells (lymphatic)
- large in the infant and after puberty is replaced by adipose and areolar connective tissue
Lymph nodes
- encapsulated oval structures located along lymphatic vessels
- contain T cells, macrophages, follicular dendritic cells, B cells
- site of proliferation of plasma cells and T cells
How does lymph enter nodes?
lymph enters nodes through afferent lymphatic vessels, is filtered to remove damaged cells and microorganisms, and exits through efferent lymphatic vessels
What occurs to foreign substances filtered by lymph nodes
- they are trapped by nodal reticular fibers
- macrophages then destroy some foreign substances by phagocytosis
- lymphocytes dstroy others by immune responses
Sentinel Node
the first lymph node that receive lymph drainage from a body area suspected of cancer
Spleen
- the largest mass of lymphatic tissue in the body
- found in the left hypochondriac region between the fundus of the stomach and the disphragm
- consists of white and red pulp
White pulp
lymphatic tissue of the spleen
- mostly contains lymphocytes on reticular fibers
What do the T lymphocytes of the white pulp (lymphatic tissue) do?
manage immune response and directly attach and destroy antigens in the blood
What do the B lymphocytes of the white pulp (lymphatic tissue) do?
develop into antibody producing plasma cells, and the antibodies inactivate antigens in blood, marking them for destruction by phagocytosis
What do the macrophages of the white pulp (lymphatic tissue) do?
Macrophages destroy antigens in blood by phagocytosis and help activate T cells
Dendritic Cells
capture antigens and deliver them to lymph nodes; also help activate T cells
Red Pulp
lymphatic tissue of the spleen
- consists of venous sinuses filled with blood and splenic cords consisting of RBCs, macrophages, lymphocytes, plasma cells, and granulocytes
What do the macrophages of the Red Pulp do?
Macrophages remove worn-out or defective RBCs, WBCs, and platelets
How does the spleen interact with the red pulp?
the spleen stores blood platelets in the red pulp
What is the red pulp involved in?
the production of blood cells during the second trimester of pregnancy
What may be required in the event the spleen is damaged in abdominal trauma?
Splenectomy may be required to prevent excessive bleeding
Lymphatic Nodules
- oval-shaped concentrations of lymphatic tissue
- scattered throughout the lamina propria of mucous membranes lining the GI tract, respiratory airways, urinary tract, and reproductive tract
- this is the mucosa-associated lymphatic tissue (MALT)
Peyer’s Patches
- lymphatic nodules in the ileum of the small intestine
- aids in destruction of bacter, preventing them from breaching intestinal wall (also Appendix)
- generate “memory” lymphocytes (also Appendix)
Tonsils
multiple aggregations of large lymphatic nodules embedded in a mucous membrane at the junction of the oral cavity and the pharynx
- function is to gather and remove pathogens in food or air
What do the tonsils include? (4)
- palatine: posteior end of oral cavity; largest
- lingual: lump collection of follicles at base of tongue
- pharyngeal (adenoids): located in posterior wall of nasopharynx
- tubal: surround openings of auditory tubes into pharynx
Why are tonsils situated strategically?
to protect against invasion of foreign substances and participate in immune responses by producing lymphoctes and antibodies
What are lymphatic vessels developed from?
lymphatic vessels develop from lymph sacs, which develop from veins.
Thus, derived from mesoderm
What are lymph nodes derived from?
lymph nodes develop from lymph sacs that become invaded by mesenchymal cells
Immunity
defensive mechanism against foreign substances that could harm body (antigens)
Innate
- non-specific resistance; born with it; one size fits all
- present at birth and refers to a wide variety of body responses against a wide range of pathogens and their toxins
- contains 1st and 2nd lines of defense
First Line of Defense
- Skin and mucous membranes
- nonspecific resistance (innate)
- mechanical protection (physical) and chemical protection (cellular)
Mechanical Protection
includes the intact epidermis layer of the skin, mucous membranes, the lacrimal apparatus, saliva, mucus, cilia, the epiglottis, and the flow of urine. Defecation and vomiting may be considered mechanical because expel microbes
Chemical Protection
localized on the skin (sebum), in loose connective tissue, stomach (gastric juice), and vagina (secretions are acidic)
Sebum
Chemical Protection
- produced by the skin
- has a low pH due to the presence of unsaturated fatty acids and lactic acid
Lysozyme
Chemical Protection
an enzyme component of sweat that also has antimicrobial properties
Gastric Juice
Chemical Protection
renders the stomach nearly sterile becasue its low pH (1.5 - 3.0) kills many bacteria and destroys most of their toxins
Second Line of Defense
Internal Defenses
- involves internal antimicrobial proteins, phagocytic and natural killer cells, inflammation, and fever
- Antimicrobial Proteins, Natural Killer Cells and Phagocytes, Inflammation, and Fever
Antimicrobial Proteins
Second Line; Internal
proteins that interfere or inhibit viral replication
Interferons
Second Line; Internal
- proteins produced by body cells infected with viruses (IFNs)
- bind to surface receptors of uninfectedcells to synthesize antiviral proteins and enhance activity of phagocytes and NK cells, inhibit cell growth, and upress tumor formation
Complement System
Second Line; Internal
group of about 20 proteins present in blood plasma and on cell membranes that “complement” or enhance certain immune, allergic, and inflammatory reactions
Natural Killer Cells
Second Line; Internal
- lymphocytes that lack the membrane molecules that identify T and B cells
- have ability to kill a wide variety of infectious microbes or certain tumor cells
What type of cells do NK cells attack?
attack body cells that display abnormal or unusual plasma membrane proteins
How do NK Cells destroy target cells?
binds to a target cell and release granules which contain toxic substance such as perforing or granzymes which destroy the target cell
Phagocytes
Second Line; Internal
cells specialized to perform phagocytosis and include neutrophils and macrophages
What do the phases of phagocytosis include?
chemotaxis, adherence, ingestion, digestion, and killing
What occurs after phagocytosis has been accomplished?
A phagolysosome is formed. The lysosome in the phagolysosome, along with lethal oxidants produced by the phagocyte, quickly kills many types of microbes
What are some reasons a microbe may evade phagocytosis?
- capsule formation
- toxin production
- interference with lysozyme secretion
- microbe’s ability to counter oxidants produced by the phagocytes
When does inflammation occur?
Second Line; Internal
occurs when cells are damaged by microbes, physical agents, or chemical agents
What are the four symptoms of inflammation?
- redness
- pain
- heat
- swelling
- loss of function may be 5th symptom, depending on site and extent of injury
What are the three basic stages of inflammation?
- vasodilation and increased permeability of blood vessels
- phaocyte migration
- tissue repair
What substances contribue to inflammation?
- histamines
- kinis
- prostaglandins
- leukotrienes
- complement
Pus
- dead phagocytes and damaged tissue and fluid
- must drain out of body or it accumulated in a confined space, causing an abscess
What causes fever?
infection from bacteria (and their toxins) and viruses
Immunity
Specific Resistance
the ability of the body to defend itself against specific invading agents
Antigens
- substances recognized as foreign by the immune responses
- both immunogenic and reactive
- large, complex molecules (most often proteins)
What are the distinguishing properties of immunity?
specificity and memory
Origin and Maturation of T cells and B cells
- both derive in bone marrow
- B cells complete development in bone marrow
- T cells migrate to the thymus to mature
What are the 2 main types of Immune Response?
- Cell-mediated immunity (CMI)
- antibody-mediated (humoral) immunity (AMI)
- a pathogen often provokes both types of immune responses
Cell-mediated immunity (CMI)
- destruction of antigens by T cells
- particularly effective against intracellular pathogens, such as fungi, parasites, and viruses; some cancer cells; and foreign tissue transplants
- always involves cells attacking cells
Antibody-mediated immunity (AMI)
- destruction of antigens by antibodies
- works mainly against antigens dissolved in body fluids and extracellular pathogens, primarily bacteira, that multiply in body fluid but rarely enter body cells
Cytokins
- small protein hormones needed for many normal cell functions
- some have been used to treat certain types of cancer
Filariasis
disease caused by blockage of lymphatic vessel
Lymphangitis
inflamed lymphatic vessels appear as painful red lines under the skin due to the vasa vasorum becoming congested with blood
Wukereria bancrefti
filaria that blocks the lymphatic vessel
Elephantiasis
Filariasis occurring in the leg
What is the name of Filariasis occurring in the scrotum?
Testicular Filariasis
What are the 5 principal antibody classes?
IgG, IgA, IGM, IgD, IgE
What are the functions of antibodies? (6)
- neutralizing antigen
- immobilization of bacteria
- agglutination and precipitation of antigen
- activation of complement
- enhancing phagocytosis
- providing fetal and newborn immunity
Monoclonal Antibodies
pure antibodies produced by fusing a B cell with a tumor cell that is capable of proliferating endlessly. Resulting cell is a hybridoma
Why are monoclonal antibodies important?
- measuring levels of a drug in a patient’s blood and in diagnosis of pregnancy, allergies, and diseases such as hepatits, rabies, and some STDs
- early detection of cancer and extent
- may be useful in preparing vaccines and treat autoimmune diseases
What are the four basic typyes of hypersensitivity reactions?
- anaphylaxis
- cytotoxic
- immune complex
- cell-mediated
Anaphylaxis Reaction
- results from interaction of allergens with IgE antibodies on surface of mast cells and basophils
- most common and occurs within a few minutes
- anaphylaxis shock: wheezing and shortness of breath as airways constrict accompanied by shock due to vasodilation and fluid loss from blood
Cytotoxic Reaction
- results from antibodies (IgG or IgM) directed against a person’s blood cells or tissue cells
Immune Complex Reactions
- involve antigens (not part of a host tissue cell), antibodies (IgA or IgM), and complement
- inclide glomerulonephritis, systemic lupus erythematosus, and rheumatoid arthritis
Cell-mediated
delayed hypersensitivity reactions that usually
appear 12-72 hours after exposure to an allergen and occur when allergens are taken up by antigen-presenting cells that migrate to lymph nodes and present the allergen to T cells
